The present invention relates to a rubber composition and a tire comprising thereof.
Environmental problems have become serious, and the regulation of suppressing discharge of CO2 is strengthened. And also, supply amount is decreased year by year due to finite of petroleum raw materials. Therefore, the inflation of petroleum price is expected in future and there is limitation for use of the compound of a rubber composition comprising petroleum resources such as a styrene-butadiene rubber, carbon black and the like. Accordingly, anticipating the depletion of petroleum in future, it is necessary to use resources other than petroleum such as a natural rubber and fillers such as silica and calcium carbonate for the rubber composition.
However, rubber components obtained from resources other than petroleum such as a natural rubber have a problem that they are easily deteriorated by external factors such as environment using a rubber composition. In particular, in case of a rubber composition for a tire used under irradiation of sun light, cracks are easily generated in the rubber composition by absorbing ultraviolet rays by rubber components; therefore there is a problem in the weather resistance of the rubber composition. Accordingly, ultraviolet rays have been recently shielded or absorbed by compounding an antioxidant or carbon black, but both of the antioxidant and carbon black are a component derived from petroleum resources.
It has been known that a large amount of iron oxides are compounded in the rubber composition for a tire in order to improve the weather resistance of the rubber composition (see JP-A-2001-81241), but there has been a problem that the strength of the rubber composition is lowered.